The present disclosure relates generally to structured polymer films and methods for forming structured polymer films. More particularly, the disclosure relates to sample processing articles and methods for producing the sample processing articles.
A variety of devices or articles have been designed for the simultaneous processing of chemical, biochemical, and other reactions. The devices include a number of wells or process chambers in which the processing is performed. Detection of various analytes or process products may be performed by detecting signal light emitted from the process chambers. The signal light may be caused by, e.g., reactions within the process chambers. In other instances, the signal light may be in response to excitation by interrogating light directed into the process chamber from an external source (e.g., a laser, etc.), where the signal light results from, e.g., chemiluminescence, etc.
Regardless of the mechanism or technique used to cause the emission of signal light from the process chambers, its detection and correlation to specific process chambers may be required. If, for example, the signal light emitted from one process chamber is attributed to a different process chamber, erroneous test results may result. The phenomenon of signal light emitted from a first process chamber and transmitted to a second process chamber is commonly referred to as “cross-talk.” Cross-talk can lead to erroneous results when, for example, the second process chamber would not emit any signal light alone, but the signal light transmitted to the second process chamber from the first process chamber is detected and recorded as a false positive result.
Attempts to avoid cross-talk have included increasing the distance between the process chambers such that any signal light reaching the second process chamber is too weak to register as a positive result with a detector. Other approaches include masking or shrouding the process chambers using an external device located over the process chambers such as is described in International Publication No. WO 02/01180 A2. One problem with these approaches is that process chamber density on a device may be limited, resulting in a less than desired number of tests being performed on a given sample processing device. Another potential problem with these approaches is that they require the use of articles or materials (e.g., masks, shrouds, etc.) in addition to the sample processing devices, thus increasing the cost and complexity of using the sample processing devices.
Another situation in which the issue of isolation between process chambers from cross-talk may arise in the delivery of interrogating light to the process chambers. For example, it may be desired that not all of the process chambers be interrogated at the same time. In other words, the process chambers may be interrogated serially (i.e., one at a time) or only selected groups of process chambers may be interrogated at the same time. In such a situation, it may be preferred that none or limited amounts of the interrogating light be transmitted to the process chambers that are not the subject of interrogation. With known processing devices, the control over interrogating light may require the use of masks or shrouds, thus raising the same problems of limited process chamber density, as well as the cost and complexity added by the additional articles/process steps.
Other problems associated with processing articles include control over the feature size, shape, and location. For example, it may be desired that variations in process chamber sizes, shapes, locations, etc., as well as the size, shape and location of other features in the devices (e.g., delivery conduits, loading chambers, etc.) be limited. Variations in feature size may detrimentally affect test accuracy by, e.g., changing the volume of analyte in the different process chambers. Further, variations in feature size may require additional sample volume to, e.g., ensure filling of all process chambers, etc. Variations in feature shape may, e.g., affect the signal light density emitted from a process chamber. Variations in feature location may, e.g., reduce test accuracy if process chamber location is not repeatable between different processing devices.
It is known to emboss polymer films using a rotating drum. The rotating drum can have a plurality of molds disposed around its circumference. The molds may be convex (i.e., male) or concave (i.e., female) molds, and are sized to provide the desired final embossed pocket dimensions, accounting for the thickness of the film, the depth of the pocket, and the thermal contraction of the film after molding or embossing. An exemplary method for producing processing articles using a rotary mold is described in U.S. 2005/0079101.
In the production of an embossed film using a convex rotary mold, a web of material is incrementally heated to its softening temperature, and is then guided to pass around the periphery of the drum. The softened material drapes over the molds and comes into close contact with generally the entire side surfaces of the convex molds except for those portions of the web located between adjacent convex molds. At the same time, the web is vacuum-drawn against the molds to urge the web into the spaces between adjacent molds. Rotary molds used in vacuum forming as described above are generally constructed by stacking a plurality of drum sections as described in U.S. Pat. No. 5,800,772. When a plurality of drum sections are assembled together, a forming tool is created. The space between the drum sections enables the use of vacuum to draw down a molten web to form pocket features.
For producing very small features in a polymer sheet, it is known to emboss a polymer web of material between a mold tool and a nip roll formed of steel or chrome. The thickness of the web exceeds the height of features on the tool, such that features are formed on the side of the web in contact with the tool features, and the backside of the web (in contact with the nip roll) is completely flat and featureless.